The prior art discloses thin-wall sleeve forming to provide teeth or splines used to transmit torque. Such prior thin-wall sleeve forming and apparatus for performing the forming are disclosed by the references discussed below.
U.S. Pat. No. 3,286,329 discloses a process for manufacturing a gear by explosively deforming a metallic outer shell to include teeth and thereafter filling the interior of the toothed shell with a filler material preferably taught to be aluminum, a synthetic resin, or a liquid. To perform the forming, the metallic shell blank is mounted on a recessed die and immersed within a liquid in which the explosion takes place to deform the blank to the recessed shape of the die and thereby form the shell teeth. Thereafter, the interior of the toothed shell is filled to provide support to the teeth.
U.S. Pat. No. 3,982,415 discloses a power transmission member having a thin-wall sleeve that is formed by a rolling process to include splines. The spline forming is performed by initially mounting the sleeve on a toothed mandrel between a pair of dies embodied by elongated racks. Movement of the die racks meshes the rack and mandrel teeth with the sleeve therebetween to form the splines.
U.S. Pat. No. 4,028,922 discloses thin-wall sleeve forming apparatus including a pair of dies, each of which has at least two tooth groups for cooperating with a toothed mandrel to perform splining by meshing of the die and mandrel teeth with the thin-wall sleeve between the meshing teeth. A leading tooth group of each die has teeth spaced farther from each other than the teeth of a following tooth group such that a first set of splines is initially formed and a second set of splines is thereafter formed between the first set. Also, either reverse movement of the dies in one embodiment or an additional trailing tooth group of farther spaced teeth is utilized to mesh farther spaced teeth with the formed splines while skipping at least alternating locations between the splines to correct any out of roundness of the splined sleeve.
U.S. Pat. No. 4,155,237 discloses a thin-wall sleeve splining machine including an automatic loader used in cooperation with a mandrel and a pair of toothed dies that form splines or teeth in a thin-wall sleeve by meshing of die and mandrel teeth with the sleeve between the meshing teeth.
Also, prior gears or sprockets for vehicle timing chains have been made with a thin-walled toothed outer sleeve of metal that is mounted on an annular wall which supports the sprocket on a central hub. The teeth are formed in the sleeve by radial tool segments displaced by movement of the press ram into associated die recesses.
Additional references which disclose thin-wall sleeve forming or other forming include U.S. Pat. Nos.: 874,448; 2,654,942; 2,724,975; 2,729,110; 2,923,166; 3,347,082; 3,396,570; and 4,131,032.